Rate determination

Abstract

Techniques for performing low-latency blind rate detection of a frame, wherein the frame is divided into a plurality of sub-segments. In an exemplary embodiment, symbols of a primary sub-segment of a frame are received and deinterleaved to recover information bits and at least one quality metric for each of a plurality of rate hypotheses. Symbols of a secondary sub-segment of the frame are also received and deinterleaved to recover information bits and at least one quality metric for each of the plurality of rate hypotheses. The recovered information bits and quality metrics for each rate hypothesis may be compared between the primary and secondary sub-segments to select the most likely rate hypothesis. In an exemplary embodiment, the at least one quality metric may include a frame quality indicator (FQI) such as a cyclical redundancy check (CRC).

1 . A method for performing blind rate detection of a frame, the frame comprising a plurality of sub-segments, the method comprising:
 deinterleaving symbols of a primary sub-segment of the frame;   for each of a plurality of rate hypotheses, recovering information bits based on symbols comprising the deinterleaved symbols of the primary sub-segment;   for each of the plurality of rate hypotheses, generating at least one quality metric based on symbols comprising the deinterleaved symbols of the primary sub-segment;   deinterleaving symbols of a secondary sub-segment of the frame;   for each of the plurality of rate hypotheses, recovering information bits based on symbols comprising the deinterleaved symbols of the secondary sub-segment;   for each of the plurality of rate hypotheses, generating at least one quality metric based on symbols comprising the deinterleaved symbols of the secondary sub-segment; and   based on the recovered information bits and quality metrics for the primary and secondary sub-segments, selecting a candidate rate hypothesis using a rate detection algorithm.   
   
   
       2 . The method of  claim 1 , the at least one quality metric comprising a frame quality indicator (FQI), the rate detection algorithm comprising determining whether the FQI for the primary sub-segment and the FQI for the secondary sub-segment are both successes. 
   
   
       3 . The method of  claim 1 , the rate detection algorithm comprising determining whether the recovered information bits for the primary sub-segment are identical to the recovered information bits for the secondary sub-segment. 
   
   
       4 . The method of  claim 2 , the rate detection algorithm further comprising determining whether the recovered information bits for the primary sub-segment are identical to the recovered information bits for the secondary sub-segment. 
   
   
       5 . The method of  claim 1 , the primary sub-segment being an eighth sub-segment of the frame, the secondary sub-segment being a sixteenth sub-segment of the frame. 
   
   
       6 . The method of  claim 1 , the primary sub-segment being the first sub-segment of the frame, the secondary sub-segment being the second sub-segment of the frame 
   
   
       7 . The method of  claim 1 , the symbols of the frame encoded according to the W-CDMA standard, the sub-segment of the frame comprising a slot. 
   
   
       8 . The method of  claim 1 , the symbols of the frame encoded according to the cdma-2000 standard, the sub-segment of the frame comprising a power control group (PCG). 
   
   
       9 . The method of  claim 1 , the recovering information bits comprising decoding deinterleaved symbols. 
   
   
       10 . The method of  claim 2 , the frame quality indicator comprising a cyclical redundancy check (CRC). 
   
   
       11 . The method of  claim 1 , further comprising:
 deinterleaving symbols of a subsequent secondary sub-segment of the frame, the subsequent secondary sub-segment of the frame following the secondary sub-segment of the frame;   for each of the plurality of rate hypotheses, recovering information bits based on symbols comprising the deinterleaved symbols of the subsequent secondary sub-segment;   for each of the plurality of rate hypotheses, generating at least one quality metric based on symbols comprising the deinterleaved symbols of the subsequent secondary sub-segment; the selecting a candidate rate hypothesis further being based on the recovered information bits and quality metrics for the subsequent secondary sub-segment.   
   
   
       12 . The method of  claim 1 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the secondary sub-segment. 
   
   
       13 . The method of  claim 12 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the secondary sub-segment. 
   
   
       14 . An apparatus for performing blind rate detection of a frame, the frame comprising a plurality of sub-segments, the apparatus comprising:
 a deinterleaver configured to deinterleave symbols of a primary sub-segment and a secondary sub-segment of the frame;   a decoding module configured to, for each of a plurality of rate hypotheses, recover information bits based on symbols comprising the deinterleaved symbols of the primary sub-segment, and to recover information bits based on symbols comprising the deinterleaved symbols of the secondary sub-segment;   a quality metric generator configured to, for each of a plurality of rate hypotheses, generate at least one quality metric based on symbols comprising the deinterleaved symbols of the primary sub-segment, and to generate at least one quality metric based on symbols comprising the deinterleaved symbols of the secondary sub-segment; and   a rate detection module configured to, based on the recovered information bits and quality metrics for the primary and secondary sub-segments, select a candidate rate hypothesis using a rate detection algorithm.   
   
   
       15 . The apparatus of  claim 14 , the at least one quality metric comprising a frame quality indicator (FQI), the rate detection algorithm comprising determining whether the FQI for the primary sub-segment and the FQI for the secondary sub-segment are both successes. 
   
   
       16 . The apparatus of  claim 14 , the rate detection algorithm comprising determining whether the recovered information bits for the primary sub-segment are identical to the recovered information bits for the secondary sub-segment. 
   
   
       17 . The apparatus of  claim 14 , the symbols of the frame encoded according to the W-CDMA standard, the sub-segment of the frame comprising a slot. 
   
   
       18 . The apparatus of  claim 14 , the symbols of the frame encoded according to the cdma-2000 standard, the sub-segment of the frame comprising a power control group (PCG). 
   
   
       19 . The apparatus of  claim 15 , the frame quality indicator comprising a cyclical redundancy check (CRC). 
   
   
       20 . The apparatus of  claim 14 :
 the deinterleaver further configured to deinterleave symbols of a subsequent secondary sub-segment of the frame, the subsequent secondary sub-segment of the frame following the secondary sub-segment of the frame;   the decoding module further configured to, for each of a plurality of rate hypotheses, recover information bits based on symbols comprising the deinterleaved symbols of the subsequent secondary sub-segment;   the quality metric generator further configured to, for each of a plurality of rate hypotheses, generate at least one quality metric based on symbols comprising the deinterleaved symbols of the subsequent secondary sub-segment; and   the rate detection module further configured to select the candidate rate hypothesis based on the recovered information bits and quality metrics for the subsequent secondary sub-segments.   
   
   
       21 . The apparatus of  claim 14 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the secondary sub-segment. 
   
   
       22 . The apparatus of  claim 21 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the secondary sub-segment. 
   
   
       23 . An apparatus for performing blind rate detection of a frame, the frame comprising a plurality of sub-segments, the apparatus comprising:
 means for deinterleaving symbols of a primary sub-segment and a secondary sub-segment of the frame;   means for recovering information bits based on symbols comprising the deinterleaved symbols of the primary sub-segment, and based on symbols comprising the deinterleaved symbols of the secondary sub-segment, for each of a plurality of rate hypotheses;   means for generating at least one quality metric based on symbols comprising the deinterleaved symbols of the primary sub-segment, and based on symbols comprising the deinterleaved symbols of the secondary sub-segment, for each of the plurality of rate hypotheses; and   means for selecting a candidate rate hypothesis using a rate detection algorithm.   
   
   
       24 . The apparatus of  claim 23 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the secondary sub-segment. 
   
   
       25 . The apparatus of  claim 24 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the secondary sub-segment. 
   
   
       26 . A computer program product for performing blind rate detection of a frame, the frame comprising a plurality of sub-segments, the product comprising:
 computer-readable medium comprising:   code for causing a computer to deinterleave symbols of a primary sub-segment and a secondary sub-segment of the frame;   code for causing a computer to recover information bits based on symbols comprising the deinterleaved symbols of the primary sub-segment, and based on symbols comprising the deinterleaved symbols of the secondary sub-segment, for each of a plurality of rate hypotheses;   code for causing a computer to generate at least one quality metric based on symbols comprising the deinterleaved symbols of the primary sub-segment, and based on symbols comprising the deinterleaved symbols of the secondary sub-segment, for each of the plurality of rate hypotheses; and   code for causing a computer to select a candidate rate hypothesis using a rate detection algorithm.   
   
   
       27 . The computer program product of  claim 26 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of at least one sub-segment prior to the secondary sub-segment. 
   
   
       28 . The computer program product of  claim 26 , the symbols comprising the deinterleaved symbols of the primary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the primary sub-segment, the symbols comprising the deinterleaved symbols of the secondary sub-segment further comprising deinterleaved symbols of all sub-segments prior to the secondary sub-segment.